Aluminum extrusion is a technique used to transform aluminum alloy into objects with a definitive cross-sectional profile for a wide range of uses. The extrusion process makes the most of aluminum’s unique combination of physical characteristics. Its malleability allows it to be easily machined and cast, and yet aluminum is one third the density and stiffness of steel so the resulting products offer strength and stability, particularly when alloyed with other metals.
Aluminum extrusion is Spectra’s specitalty, and over decades of manufacturing, we have mastered the process. Let’s look at each step in the process of making aluminum extrusion.
After designing and creating the shape of the die, a cylindrical billet of aluminum alloy is heated to 800°F-925°F to prepare it for the extrusion process. This high temperature softens the aluminum, making it more malleable and easier to shape.
The heated aluminum billet is then transferred to a loader, where a lubricant is added to prevent it from sticking to the extrusion machine, the ram, or the handle. This lubrication process ensures smooth and efficient extrusion without causing any damage to the equipment.
Substantial pressure is applied to a dummy block using a ram, which pushes the aluminum billet into the container, forcing it through the die. This process, known as extrusion, shapes the aluminum into the desired profile as it passes through the die’s opening under high pressure.
To avoid the formation of oxides, nitrogen in liquid or gaseous form is introduced and allowed to flow through the sections of the die. This creates an inert atmosphere within the die, preventing oxidation of the aluminum during the extrusion process. By minimizing oxidation, the quality of the extruded aluminum is improved, and the lifespan of the die is extended.
The extruded part emerges from the die onto a run-out table as an elongated piece that is now the same shape as the die opening. It is then pulled to the cooling table where fans cool the newly created aluminum extrusion. The rapid cooling process helps to set the shape of the extrusion and prevents deformation.
Once the cooling process is completed, the extruded aluminum is moved to a stretcher, where it undergoes straightening and work hardening. This step ensures that the extrusions meet the required dimensional tolerances and mechanical properties.
The hardened extrusions are brought to the saw table and cut according to the required lengths. Precision cutting ensures that the extruded aluminum pieces are uniform in size and ready for further processing or assembly into finished products.
The final step in the extrusion process is to treat the extrusions with heat in age ovens, which hardens the aluminum by speeding up the aging process. This heat treatment further enhances the mechanical properties of the aluminum, such as strength and hardness, making it suitable for its intended application.
Additional complexities may be applied during this process to further customize the extruded parts. For example, to create hollow sections, pins or piercing mandrels are placed inside the die. After the extrusion process, a variety of options are available to adjust the colour, texture and brightness of the aluminum’s finish. This may include aluminum anodizing or painting.
Aluminum extrusion is used in all sorts of products that we use in our daily lives. Read more about aluminum extrusion and it’s applications in various industries from our blog articles and other informational pages:
Canadian aluminum manufacturer since 1978